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Subject[PATCH 3/5] iio: adc: stm32-dfsdm: manage data resolution in trigger mode
Date
Add output sample resolution management in scan mode.
Add stm32_dfsdm_process_data() function to share sample
processing between continuous and trigger modes.

Signed-off-by: Olivier Moysan <olivier.moysan@st.com>
---
drivers/iio/adc/stm32-dfsdm-adc.c | 41 ++++++++++++++++++++++++++-------------
1 file changed, 28 insertions(+), 13 deletions(-)

diff --git a/drivers/iio/adc/stm32-dfsdm-adc.c b/drivers/iio/adc/stm32-dfsdm-adc.c
index 6b90a40882f2..5b19a88412a6 100644
--- a/drivers/iio/adc/stm32-dfsdm-adc.c
+++ b/drivers/iio/adc/stm32-dfsdm-adc.c
@@ -779,6 +779,30 @@ static unsigned int stm32_dfsdm_adc_dma_residue(struct stm32_dfsdm_adc *adc)
return 0;
}

+static inline void stm32_dfsdm_process_data(struct stm32_dfsdm_adc *adc,
+ s32 *buffer)
+{
+ struct stm32_dfsdm_filter *fl = &adc->dfsdm->fl_list[adc->fl_id];
+ struct stm32_dfsdm_filter_osr *flo = &fl->flo;
+ unsigned int i = adc->nconv;
+ s32 *ptr = buffer;
+
+ while (i--) {
+ /* Mask 8 LSB that contains the channel ID */
+ *ptr &= 0xFFFFFF00;
+ /* Convert 2^(n-1) sample to 2^(n-1)-1 to avoid wrap-around */
+ if (*ptr > flo->max)
+ *ptr -= 1;
+ /*
+ * Samples from filter are retrieved with 23 bits resolution
+ * or less. Shift left to align MSB on 24 bits.
+ */
+ *ptr <<= flo->lshift;
+
+ ptr++;
+ }
+}
+
static irqreturn_t stm32_dfsdm_adc_trigger_handler(int irq, void *p)
{
struct iio_poll_func *pf = p;
@@ -787,7 +811,9 @@ static irqreturn_t stm32_dfsdm_adc_trigger_handler(int irq, void *p)
int available = stm32_dfsdm_adc_dma_residue(adc);

while (available >= indio_dev->scan_bytes) {
- u32 *buffer = (u32 *)&adc->rx_buf[adc->bufi];
+ s32 *buffer = (s32 *)&adc->rx_buf[adc->bufi];
+
+ stm32_dfsdm_process_data(adc, buffer);

iio_push_to_buffers_with_timestamp(indio_dev, buffer,
pf->timestamp);
@@ -806,8 +832,6 @@ static void stm32_dfsdm_dma_buffer_done(void *data)
{
struct iio_dev *indio_dev = data;
struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
- struct stm32_dfsdm_filter *fl = &adc->dfsdm->fl_list[adc->fl_id];
- struct stm32_dfsdm_filter_osr *flo = &fl->flo;
int available = stm32_dfsdm_adc_dma_residue(adc);
size_t old_pos;

@@ -832,16 +856,7 @@ static void stm32_dfsdm_dma_buffer_done(void *data)
while (available >= indio_dev->scan_bytes) {
s32 *buffer = (s32 *)&adc->rx_buf[adc->bufi];

- /* Mask 8 LSB that contains the channel ID */
- *buffer &= 0xFFFFFF00;
- /* Convert 2^(n-1) sample to 2^(n-1)-1 to avoid wrap-around */
- if (*buffer > flo->max)
- *buffer -= 1;
- /*
- * Samples from filter are retrieved with 23 bits resolution
- * or less. Shift left to align MSB on 24 bits.
- */
- *buffer <<= flo->lshift;
+ stm32_dfsdm_process_data(adc, buffer);

available -= indio_dev->scan_bytes;
adc->bufi += indio_dev->scan_bytes;
--
2.7.4
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